Hi, I made a widget to display a popup style box using CSS only.  It works well in preview, everything work, however when I put it live on the site.  It does not work.  Can you guys tell me what is wrong?

HTML

<a class="button" href="#{{uc_id}}pop" id="{{uc_id}}">{{button_text|raw}}</a>

<section id="{{uc_id}}pop">
<div class="{{uc_id}}popup">
<h2>{{popup_title|raw}}</h2>
<a class="{{uc_id}}close" href="#">×</a>
<div class="{{uc_id}}content">
{{popup_content|raw}}
</div>
</div>
</section>

CSS

#{{uc_id}} {
  padding: {{button_text_padding}}px;
  background: {{button_background_color}};
  border: {{button_border_size}}px solid {{button_border_color}};
  border-radius: {{button_border_radius}}px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease-out;
  display: inline-block;
}

#{{uc_id}}:hover {
  background: {{button_hover_color}};
}

#{{uc_id}}pop {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0, 0, 0, 0.7);
  transition: opacity 500ms;
  display: none;
  opacity: 0;
}

#{{uc_id}}pop:target {
  display: block;
  opacity: 1;
}

.{{uc_id}}popup {
  margin: 70px auto;
  padding: 20px;
  background: #fff;
  border-radius: 5px;
  width: 30%;
  position: relative;
  transition: all 5s ease-in-out;
}

.{{uc_id}}popup h2 {
  margin-top: 0;
  color: {{popup_title_color}};
}
.{{uc_id}}popup .{{uc_id}}close {
  position: absolute;
  top: 20px;
  right: 30px;
  transition: all 200ms;
  font-size: 30px;
  font-weight: bold;
  text-decoration: none;
  color: #333;
}
.{{uc_id}}popup .{{uc_id}}close:hover {
  color: #06D85F;
}
.{{uc_id}}popup .{{uc_id}}content {
  max-height: 30%;
  overflow: auto;
}

@media screen and (max-width: 700px){
  .{{uc_id}}popup{
    width: 70%;
  }
}